Fluorescence from <i>S</i>2 single vibronic levels in thiophosgene vapor: Quantum yields and quenching effects

Abstract

The quantum yields of fluorescence from the second excited singlet state of thiophosgene vapor have been measured as a function of pressure for eight S2←S0 transitions, and parameters for the decay of the levels pumped have been calculated. The results indicate that reassignment of the origin of the S2←S0 band system to 35 112 from 36 007 cm−1 is necessary. Quantum yields of fluorescence from the lowest levels in S2 are extremely high (0.50 to 1.0) and are indicative of a very slow radiationless decay rate. Weakening of fluorescence from higher S2 vibrational levels is most likely caused by predissociation.